U.S. patent number 5,160,771 [Application Number 07/588,752] was granted by the patent office on 1992-11-03 for joining metal-polymer-metal laminate sections.
This patent grant is currently assigned to Structural Laminates Company. Invention is credited to James A. Colpo, William C. Herbein, Cynthia L. T. Lambing.
United States Patent |
5,160,771 |
Lambing , et al. |
November 3, 1992 |
Joining metal-polymer-metal laminate sections
Abstract
A metal-polymer-metal laminate is made by joining adjacent
laminate sections in a staggered relationship. Terminal portions of
metal layers in a first laminate section are opposed to ends of
fiber-reinforced polymer layers in a second laminate section. End
portions of fiber-reinforced polymer layers in the first laminate
section are opposed to ends of metal layers in a second laminate
section. The two laminate sections are then joined by an adhesive
layer.
Inventors: |
Lambing; Cynthia L. T.
(Kiskiminetas, PA), Colpo; James A. (Murrysville, PA),
Herbein; William C. (Murrysville, PA) |
Assignee: |
Structural Laminates Company
(New Kensington, PA)
|
Family
ID: |
24355149 |
Appl.
No.: |
07/588,752 |
Filed: |
September 27, 1990 |
Current U.S.
Class: |
428/57; 156/157;
156/182; 428/189; 428/192; 428/33; 428/457; 428/458; 428/58;
428/60; 428/77 |
Current CPC
Class: |
B29C
66/12821 (20130101); B29C 66/12822 (20130101); B29C
66/1284 (20130101); B29C 66/12841 (20130101); B29C
66/12842 (20130101); B29C 66/14 (20130101); B29C
66/721 (20130101); B29C 66/1248 (20130101); B29C
66/43 (20130101); B29C 66/72321 (20130101); B29C
66/45 (20130101); B29C 66/472 (20130101); B29L
2009/00 (20130101); Y10T 428/31681 (20150401); Y10T
428/31678 (20150401); B29C 66/7394 (20130101); B29C
66/71 (20130101); B29C 66/7212 (20130101); B29K
2307/04 (20130101); B29C 66/7212 (20130101); B29K
2309/08 (20130101); B29C 66/7212 (20130101); B29K
2277/10 (20130101); B29C 66/71 (20130101); B29K
2063/00 (20130101); B29C 66/7212 (20130101); Y10T
428/24777 (20150115); Y10T 428/19 (20150115); Y10T
428/192 (20150115); Y10T 428/195 (20150115); Y10T
428/24752 (20150115); B29C 66/7392 (20130101); B29C
65/483 (20130101) |
Current International
Class: |
B29C
65/00 (20060101); B32B 003/00 () |
Field of
Search: |
;428/33,57,58,60,77,189,192,458 ;156/157,182 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Thibodeau; Paul J.
Assistant Examiner: Kiliman; Leszek
Attorney, Agent or Firm: Klepac; Glenn E.
Claims
What is claimed is:
1. A metal-polymer-metal laminate (45) made by adhesively joining
adjacent laminate sections, said laminate (45) comprising:
(a) a first laminate section (10) comprising:
(i) a first metal layer (11);
(ii) a second metal layer (15) having a lateral end (16), said
second metal layer (15) being laterally non-coextensive with the
first metal layer (11); and
(iii) a fiber-reinforced first polymer layer (20) between said
first metal layer (10) and second metal layer (15), said first
polymer layer (20) having a lateral end (21); (b) a second laminate
section (30) comprising:
(i) a first metal layer (31) opposed to a metal layer (15);
(ii) a second metal layer (35) having a lateral end (36) opposed to
the lateral end (21) of a polymer layer (20), said second metal
layer (35) being laterally non-coextensive with the first metal
layer (31); and
(iii) a fiber-reinforced first polymer layer (40) between said
first metal layer (31) and second metal layer (35), said first
polymer layer (40) having a lateral end (41) opposed to the lateral
end (16) of a metal layer (15) in the first laminate section (10);
and
(c) an adhesive layer (50) interposed between said first and second
laminate sections (10, 30) and adhesively joining them
together.
2. The laminate of claim 1 wherein said lateral end (16) of the
second metal layer (15) and said lateral end (21) of the first
polymer layer (20) extend generally transverse to said first metal
layer (11) in the first laminate section (10).
3. The laminate of claim 1 wherein said lateral end (36) of the
second metal layer (35) and said lateral end (41) of the first
polymer layer (40) extend generally transverse to said first metal
layer (31) in the second laminate section (30).
4. The laminate of claim 1 wherein said first laminate section (10)
further comprises:
(iv) a third metal layer (60) having a lateral end (61); and
(v) a fiber-reinforced second polymer layer (65) between said
second metal layer (15) and third metal layer (60), said second
polymer layer (65) having a lateral end (66); and said second
laminate section (30) further comprises:
(iv) a third metal layer (80) having a lateral end (81) opposed to
a lateral end (21) of a polymer layer (20) in the first laminate
section (10); and
(v) a fiber-reinforced second polymer layer (85) between said
second metal layer (35) and third metal layer (30), said second
polymer layer (85) having a lateral end (86) opposed to a lateral
end (16) of a metal layer (15) in the first laminate section
(10).
5. The laminate of claim 4 wherein said first laminate section (10)
further comprises:
(vi) a fourth metal layer (101) having a lateral end (102); and
(vii) a fiber-reinforced third polymer layer (105) between said
third metal layer (60) and fourth metal layer (101), said third
polymer layer (105) having a lateral end (106); and said second
laminate section (30) further comprises:
(vi) a fourth metal layer (120) having a lateral end (121) opposed
to a lateral end (21) of a polymer layer (20) in the first laminate
section (10); and
(vii) a fiber-reinforced third polymer layer (130) between said
third metal layer (80) and fourth metal layer (120), said third
polymer layer (130) having a lateral end (131) opposed to a lateral
end (16) of a metal layer (15) in the first laminate section
(10).
6. The laminate of claim 1 wherein said adhesive layer (50) joins
said first metal layer (11) in the first laminate section (10) to
said second metal layer (35) in the second laminate section
(30).
7. The laminate of claim 4 wherein said adhesive layer (50) joins
said first metal layer (11) in the first laminate section (10) to
said third metal layer (80) in the second laminate section
(30).
8. The laminate of claim 5 wherein said adhesive layer (50) joins
said first metal layer (11) in the first laminate section (10) to
said fourth metal layer (120) in the second laminate section
(30).
9. The laminate of claim 1 wherein said metal layers (11, 15, 31,
35) each comprise an aluminum alloy.
10. The laminate of claim 1 wherein said polymer layers (20, 40)
each comprise a thermosetting epoxy resin.
11. The laminate of claim 1 wherein said adhesive layer (50)
comprises a thermosetting epoxy resin.
12. The laminate of claim 1 wherein said polymer layers (20, 40)
are reinforced with fibers comprising a material selected from the
group consisting of aramids, polyolefins, glass, carbon and
ceramics.
13. The laminate of claim 1 wherein said polymer layers (20, 40)
are reinforced with poly-p-phenylene terephthalamide fibers.
14. The laminate of claim 1 wherein said polymer layers (20, 40)
each have lesser thickness than each said metal layers (11, 15, 31,
35).
15. A metal-polymer-metal laminate (400) made by joining adjacent
laminate sections, said laminate (400) comprising:
(a) a first laminate section (200) comprising:
(i) a first metal layer (201) having a lateral edge (202);
(ii) a second metal layer (211) spaced from said first metal layer
(201) and having a lateral edge (212);
(iii) a third metal layer (221) intermediate said first metal layer
(201) and second metal layer (211), said third metal layer (221)
having a lateral edge (222) spaced laterally inwardly of the
lateral edges (202, 212) of said first and second metal layers
(201, 211);
(iv) a fiber-reinforced first polymer layer (231) between the first
and third metal layers (201, 221), said first polymer layer (231)
having a lateral edge (232) spaced laterally inwardly of the
lateral edges (202, 212) on said first and second metal layers
(201, 211); and
(v) a fiber-reinforced second polymer layer (241) between the
second and third metal layers (211, 221), said second polymer layer
(241) having a lateral edge (242) spaced laterally inwardly of the
lateral edges (202, 212) on said first and second metal layers
(201, 211);
said first, second and third metal layers (201, 211, 221) and said
first and second polymer layers (231, 241) defining a slot
(245);
(b) a second laminate section (250) comprising:
(i) first, second, third and fourth metal layers (251, 261, 271,
281), said second and third metal layers (261, 271) each having a
lateral edge (262, 272) opposed to a lateral edge (232, 242) of a
polymer layer (231, 241) in the first laminate section (200);
and
(ii) fiber-reinforced first, second and third polymer layers (301,
311, 321) between the metal layers (251, 261, 271, 281), said
polymer layers (301, 311, 321) each having a lateral edge (302,
312, 322) opposed to a lateral edge (202, 222, 212) of a metal
layer (201, 221, 211) in the first laminate section (200); and
(c) an adhesive layer (350) joining said first laminate section
(200) to the second laminate section (250).
16. The laminate of claim 15 wherein said second laminate section
(250) defines a key (345) fitted within said slot (245).
17. The laminate of claim 15 wherein said polymer layers (231, 241,
301, 311, 321) each have lesser thickness than each said metal
layers (201, 211, 221, 251, 261, 271, 281).
Description
FIELD OF THE INVENTION
The present invention relates to the joining of metal-polymer-metal
laminate sections. More particularly, the invention relates to a
laminate made by adhesively joining adjacent laminate sections in a
staggered relationship without inserting penetrating fastener
elements in the joint area.
Metal-polymer-metal laminates made with fiber-reinforced polymer
layers are now being sold in commercial quantities to the aircraft
industry. Such laminates are manufactured in panels having a size
of about 100 in.times.52 in (254 cm.times.132 cm). The maximum size
limit imposed upon the laminates by present manufacturing
technology is approximately 180 in.times.60 in (457 cm.times.152
cm). Because of these manufacturing limits, there is a need for a
method of joining adjacent panels or sections which will provide
larger structures.
BACKGROUND OF THE INVENTION
Techniques for joining adjacent laminated composite structures are
known in the prior art. However, prior art techniques generally
require insertion of fastening elements such as screws, bolts or
rivets through the structure with consequent weakening in the joint
area. One objective of the present invention is to provide a
technique for adhesively joining adjacent metal-polymer-metal
laminate sections that does not require penetration by additional
fastening elements through the structure.
Another prior art joining technique requires lapping or doubling of
adjacent laminate sections, thereby increasing stiffness in the
joint area. A second objective of the present invention is to
provide a joining technique not requiring the laminate sections to
be lapped in the joint area.
A further objective of the invention is to provide a laminate
having improved impact strength compared with laminates penetrated
by through fasteners. The laminate of the invention is also
expected to have improved tensile strength and compressive
strength.
Some prior art references disclosing joining techniques for
laminated composite structures are Morrison et al U.S. Pat. No.
4,279,676; Eichler et al U.S. Pat. No. 3,205,121; Olson U.S. Pat.
No. 3,016,316; Hoelzinger U.S. Pat. No. 4,435,237; and Aristodimou
U.S. Pat. No. 4,840,825. None of these references discloses or
suggests a metal-polymer-metal laminate made by adhesively joining
adjacent laminate sections as claimed herein.
Additional objectives and advantages of the present invention will
become apparent to persons skilled in the art from the following
detailed description.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a
metal-polymer-metal laminate made by joining adjacent laminate
sections in a staggered relationship. The term "staggered" refers
to the fact that ends of metal layers in a first laminate section
are opposed to ends of polymer layers in a second laminate section,
and that ends of polymer layers in the first laminate section are
opposed to ends of metal layers in the second laminate section.
This staggered relationship is easier to manufacture and provides
improved properties compared with laminates made by joining
adjacent sections using prior art techniques.
The metal layers employed in the laminate sections may have a
thickness of about 0.1-2.0 mm, preferably about 0.2-1.0 mm. In a
particularly preferred embodiment, the metal layers have a
thickness of about 0.0115-0.0125 in (0.29-0.32 mm). The metal
employed in such layers may be aluminum, iron, titanium, magnesium,
copper, or various alloys thereof. Aluminum alloys of the 2000,
6000, and 7000 (Aluminum Association) series are preferred. The
total number of metal layers in each section is about 2 to 20.
The polymer layers in the laminate sections may have a thickness of
about 0.1-1.5 mm, preferably about 0.15-0.8 mm. The polymer layers
preferably have lesser thickness than the metal layers. In a
particularly preferred embodiment, the polymer layers have a
thickness of about 0.008-0.009 in (0.20-0.23 mm). The total number
of polymer layers in each section may be about 1 to 19.
The polymer employed in the polymer layers may be thermosetting or
thermoplastic. Some suitable thermosets are epoxies, unsaturated
polyesters, vinyl esters, and phenolic resins. Some suitable
thermoplastics are polyamides, aromatic polyesters, polyarylates,
polyphenylene sulfide, polyether ketones, and liquid crystal
polymers. Epoxy resins are particularly preferred.
The polymer layers are reinforced with fibers having high tensile
strength. The reinforcing fibers may be glass, ceramic, carbon,
polyolefin, or aromatic polyamide. In a preferred embodiment,
poly-p-phenylene terephthalamide fibers are employed.
The adhesive layer of the invention will generally be made from the
same polymer employed in the polymer layers. Epoxy resin adhesives
are particularly preferred.
The laminate sections may be prestressed or unstressed before being
joined. A particularly preferred prestressed laminate section is
made in accordance with Schijve et al U.S. Pat. No. 4,489,123. A
particularly preferred unstressed laminate section is made in
accordance with Schijve et al U.S Pat. No. 4,500,589. The
disclosures of both said Schijve et al patents are incorporated
herein by reference to the extent consistent with the present
invention.
In two preferred embodiments, the laminate sections are prestressed
by applying an external tensile force so that a specific elongation
is applied to the entire laminate which is greater than the
specific elastic elongation of the metal sheets or layers and
smaller than the specific break elongation of the reinforcing
fibers. The specific elongation brought about by the tensile force
is about 0.2-2%, with 0.4% specific elongation in the preferred
embodiments. The metal metal layers making up the laminate sections
comprise a 7475 (Aluminum Association series) aluminum alloy in
these preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1, 2, and 3 are cross-sectional views of a first embodiment
of the invention.
FIGS. 4, 5, and 6 are cross-sectional views of a second embodiment
of the invention.
FIGS. 7, 8, and 9 are cross-sectional views of a third embodiment
of the invention.
FIGS. 10, 11, and 12 are cross-sectional views of a fourth
embodiment of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
A first embodiment of the present invention is described with
reference to FIGS. 1-3. There is shown in FIG. 1 a first laminate
section 10 comprising a first metal layer 11 having an internal
surface 12; a second metal layer 15 having a lateral end 16; and a
fiber-reinforced first polymer layer 20 between the first and
second metal layers. The first polymer layer 20 has a lateral end
21 aligned with the lateral end 16 of the second metal layer
15.
The first metal layer 11 comprises a body portion 11a joined to the
first polymer layer 20 and a lateral extension 11b extending
laterally of the body portion 11a. The body portion 11a, first
polymer layer 20, and second metal layer 15 make up a first body or
first portion of the first laminate section 10.
There is shown in FIG. 2 a second laminate section 30. The second
section 30 comprises a first metal layer 31 having an internal
surface 32; a second metal sheet 35 having a lateral end 36; and a
fiber-reinforced first polymer layer 40 between the first metal
layer 31 and second metal layer 35. The first polymer layer 40 has
a lateral end 41 generally aligned with the lateral end 36 of the
second metal layer 35.
The first metal layer 31 comprises a body portion 31a joined to the
first polymer layer 40 and a lateral extension 31b extending
laterally of the body portion 31a. The body portion 31a, first
polymer layer 40, and second metal layer 35 make up a first body or
first portion of the first laminate section 10.
There is shown in FIG. 3 a completed laminate 45 made by joining
the first laminate section 10 of FIG. 1 to the second laminate
section 30 of FIG. 2. The sections 10, 30 are joined by means of an
adhesive layer 50 applied to adjacent surfaces. As shown in FIG. 3,
the adhesive layer 50 extends laterally between the first metal
layer Il and second metal layer 35; transversely between the second
metal layer 35 and first polymer layer 20 and between the first
polymer layer 40 and second metal layer 15; and laterally between
the second metal layer 15 and first metal layer 31.
As shown in FIG. 3, the lateral end 16 of the second metal layer 15
and the lateral end 21 of the first polymer layer 20 both extend
generally transverse to the first metal layer 11. Similarly, the
lateral end 36 of the second metal layer 35 and the lateral end 41
of the first polymer layer 40 both extend generally transverse to
the first metal layer 31. As used herein, the term "generally
transverse" does not require a 90.degree. angle. Rather, it is
contemplated that surfaces or structures described as having
generally transverse orientation extend at an angle of about
45.degree. or more with respect to their respective reference
surfaces or structures.
A second embodiment of the invention is illustrated in FIGS.
4-6.
FIG. 4 shows a first laminate section 55 comprising a first metal
layer 11, a second metal layer 15, and a third metal layer 60. A
fiber-reinforced first polymer layer 20 joins the first metal layer
11 and second metal layer 15. A fiber-reinforced second polymer
layer 65 joins the second metal layer 15 and third metal layer 60.
The third metal layer 60 has a lateral end 61 aligned with a
lateral end 66 of the second polymer layer 65, as shown in FIG.
4.
A second laminate section 70 is shown in FIG. 5. The section 70
comprises first, second, and third metal layers 31, 35, 80; and
fiber-reinforced first and second polymer layers 40, 85. The third
metal layer 80 has a lateral end 81. The second polymer layer 85
has a lateral end 86 generally aligned with the end 81.
The first section 55 and second section 70 are joined together to
form a unitary-metal polymer-metal laminate 90, all shown in FIG.
6. An adhesive layer 50 adhesively bonds the two sections 55, 70 in
both transverse and lateral directions.
A third embodiment of the invention is shown in FIGS. 7-9.
A first laminate section 100 shown in FIG. 7 comprises first,
second, third, and fourth metal layers 11, 15, 60, 101; and
fiber-reinforced first, second, and third polymer layers 20, 65,
105. The fourth metal layer 101 has a lateral end 102 generally
aligned with a lateral end 106 of the third polymer layer 105.
A second laminate section 110 is shown in FIG. 8. The second
section 110 comprises first, second, third, and fourth metal layers
31, 35, 80, 120; and fiber-reinforced first, second, and third
polymer layers 40, 85, 130. The fourth metal layer 120 has a
lateral end 121 generally aligned with a lateral end 131 of the
third polymer layer 130. The end portion 121 of the youth metal
layer 120 and end 131 of the third polymer layer 130 are laterally
displaced from ends 36, 81 of the second and third metal layers 35,
80.
FIG. 9 shows a completed laminate 140 made by joining the first
laminate section 100 of FIG. 7 to the second laminate section 110
of FIG. 8. The sections 100, 110 are joined by adhesive layer 50
applied to adjacent surface portions of each structure. The
adhesive layer 50 traverses a complex path between adjacent
portions of various metal and polymer layers in the laminate
140.
A fourth embodiment of the invention is described below with
reference to FIGS. 10-12.
A first laminate section 200 shown in FIG. 10 comprises a first
metal layer 201 having a lateral edge 202 and an interior surface
203; a second metal layer 211 spaced transversely from the first
layer 200 and having a lateral edge 212 and an interior surface
213; and a third metal layer 221 between the first and second metal
layers 201, 211. The third metal layer 221 has a lateral edge 222
spaced laterally inwardly of the other lateral edges 202, 212.
The first laminate section 200 further comprises a fiber-reinforced
first polymer layer 231 having a lateral edge 232 spaced laterally
inwardly of the lateral edges 202, 212; and a fiber-reinforced
second polymer layer 241 also having a lateral edge 242 spaced
laterally of the lateral edges 202, 212. The two lateral edges 232,
242 are generally aligned in the preferred embodiment shown. A slot
245 is defined by the first and second metal layers 201, 211;
lateral edge 222; and lateral edges 232, 242.
A second laminate section 250 shown in FIG. 11 comprises first,
second, third, and fourth metal layers 251, 261, 271, 281, each
having a lateral edge 252, 262, 272, 282. Fiber-reinforced first,
second, and third polymer layers 301, 311, 321, are interposed
between the metal layers. The polymer layers 301, 311, 321 each
have a lateral edge 302, 312, 322.
As shown in FIG. 11, edges 262, 272, 312 extend laterally outwardly
of edges 252, 282, 302, 322. The portion of the second section 250
extending outwardly comprises a key 345 corresponding to the slot
245 in the first section 200.
The first section 200 and second section 250 are joined by an
adhesive layer 350 to form a unitary metal-polymer laminate 400
shown in FIG. 12. In this laminate 400, lateral edges 302, 312, 322
of the polymer layers are opposed to respective edges 202, 222,
212, of the metal layers 201, 221, 211. Lateral edges 232, 242 of
the polymer layers 231, 241 are opposed to lateral edges 262, 272
of the metal layers 261, 271.
EXAMPLES
Some examples of suitable metal-polymer-metal laminates comprising
the laminate sections of the present invention are as follows:
______________________________________ Example Metal Polymer
Stretch ______________________________________ 1 7475 T61 Aluminum
AF 163 0.4% 2 2024 T3 Aluminum AF 163 None 3 7475 T761 Aluminum AF
163 0.4% 4 2024 T81 Aluminum AF 191 None
______________________________________
The metal layers in Examples 1-4 have a thickness of about
0.0115-0.0125 in (0.29-0.32 mm).
The AF 163 polymer in Examples 1-3 is a thermosetting epoxy resin
having a cure temperature of 250.degree. F. and a maximum service
temperature of 200.degree. F. The same epoxy is employed as the
adhesive layer for joining laminate sections made in accordance
with Examples 1-3.
The AF 191 polymer in Example 4 is a thermosetting epoxy resin
having a cure temperature of 350.degree. F. and a maximum service
temperature of 300.degree. F. The same epoxy is used to join
laminate sections made in accordance with Example 4.
Each of the polymer layers has a thickness of about 0.008-0.009 in
(0.20-0.23 mm). The polymer layers are reinforced with
poly-p-phenylene terephthalamide fibers.
Laminate sections made in accordance with Examples 1 and 3 are
provided with 0.4% permanent stretch to enhance fatigue resistance.
The sections of Examples 2 and 4 are unstretched.
While the invention has been described in terms of preferred
embodiments, numerous equivalents and variations will occur to
persons skilled in the art. For example, there may be more layers
in the laminate sections than shown in the drawings. The claims
appended hereto are intended to encompass all embodiments which
fall within the spirit of the invention.
* * * * *